This invention relates to an improved method and apparatus for stabilizing cargo during transportation. More particularly, this invention relates to a novel method and apparatus for stabilizing and restraining undesired movement of drums, boxes, rigid and flexible containers, palletized or not palletized, within the interior of a transport container or the like with respect to each other and/or with respect to the internal walls of the container.
Most shipments for transport are placed in enclosures such as ship cargo holds, intermodal containers, truck trailers, truck bodies, railroad box cars, and the like. Examples of cargo in containment enclosures include fifty five gallon closed head drums, super sacks or plastic reinforced bags, plastic wrapped bundles, cased goods, metal coils, specialty heavy paper rolls, plastic or metal containers mounted on pallets, etc. Although each individual component of cargo may be quite heavy and stationary at rest, the mass of a transport load can produce considerable momentum force as a ship, railroad car, truck trailer or truck body is placed in motion, stops, or changes direction.
During ocean shipping, cargo within cargo holds or intermodal containers are subjected to wave forces including: yaw, pitch, heave, sway, and surge. Depending upon weather conditions and the size of the vessel, cargo can experience various magnitudes of shifting forces throughout the course of a transoceanic voyage.
In another transport context, railroad trains are made-up by individual box cars being rolled together in a switching yard. When a railroad car is rolled into a stationary string of cars, the impact causes the car couplings to lock together with a jolt. This impact can apply a significant force to cargo within the rail car. Moreover, during transport, railroad cars and overland transport vehicles are subject to braking forces, bumps, centrifugal forces on curves, vibration, dips in the track or road, swaying, run-in or run-out forces, etc.
In overland truck/trailer transport there are frequent brake and acceleration forces imparted to the trailer and its contents, centrifugal forces around curves, turning forces, uneven road surfaces, roadway transition junctions, roadway grades, etc.
Each of these forces has the potential to impart a substantial force to cargo during transport. When cargo contacts other cargo or the interior walls or doors of a container, the force necessary to reduce its momentum to zero must be absorbed by the goods and/or the container. Such forces can result in damage to the cargo, damage to the interior walls or doors of the container, damage to the cargo packaging, and may even create dangerous leaks if the cargo is a hazardous material. Accordingly, it is undesirable to permit cargo to gain any momentum independent of other cargo or a transport container. This can be accomplished by stabilizing the cargo within the container with respect to other cargo and/or the internal walls of the container so that the cargo and container are essentially united and operationally function as a single object during transport.
In order to stabilize cargo with respect to other cargo and the internal walls of a transport container or cargo hold, various forms of load containments, load spacers and void fillers have been used to fill the spaces between cargo and between cargo and the internal walls of an intermodal container, box car, cargo hold, truck trailer, etc. Often, load containment enclosures are secured to the floor or sides of the transport container and prevented from moving with respect to each other by specially fabricated wood or steel framing, floor blocking, rubber mats, steel strapping, or heavy air bags. A variety of dunnage materials and void fillers has been used to prevent the movement of cargo with respect to other cargo and the internal walls of the transport container. Each of these previously known systems has limitations associated with cost, lack of strength, amount of labor required for installation, time expended for installation, lack of flexibility, securement integrity, transportability and storage of spacer elements, etc.
Further to the above, in the past, various dunnage materials have been utilized within transport containers to eliminate unwanted movement or shifting of a load. Drums, boxes, or other containers have been restrained in several different ways. Primarily, cargo has been stabilized by the use of void fillers such as collapsible cardboard frames or cells. These systems use strips of corrugated cardboard configured and assembled to expand into solid rectangular frames or cells of various forms and sizes and incorporate honeycomb and/or diamond-shaped cells for space and strength considerations. These systems while useful for known rectangular voids can exhibit impaired performance due to size and/or dimension variance. Moreover curved surfaces can not be accommodated well with rectangular shaped void fillers. The difficulty in applying various rectangular units to irregular shapes and the on site adjustment for varying sizes of voids to be filled, the unsuitability of corrugated board to absorb strong compression forces, and the use of materials not fully resistant to moisture can impair use of this type of dunnage void filler system.
Other known means of restraint such as the use of inflatable dunnage bags used alone or in combination with collapsible void fillers have tended to exhibit the disadvantage that air bags are subject to rupturing, leakage and loss of air pressure, or simply contraction and securement loosening in low temperature environments.
In addition to the above, other restraining systems known in the past often required additional elements and equipment which tended to be cumbersome to store, arduous to handle and/or install, and often required a degree of skilled labor in application.
Finally, in certain instances wood block and bracing has been used in the past to fill voids and secure loads; however, wood bracing is somewhat time consuming to install and often requires skilled or semi-skilled labor which is often contracted out to third parties. In addition certain wood materials are not suitable for international transport without fumigation which increases the overall cost of the securement system.
Consequently, a need exists for securing cargo in cargo holds, transport containers, box cars, truck trailers and the like that is functionally effective, cost-efficient, and labor-efficient. Still further a need exists for load stabilization systems that have enhanced strength characteristics under a variety of environments, exhibit flexibility for loads of various types and sizes and limit cargo shifting within a container.
The problems suggested in the preceding are not intended to be exhaustive but rather are among many which may tend to reduce the effectiveness of load stabilizer methods and apparatus appearing in the past. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that load stabilizing systems appearing in the past will admit to worthwhile improvement.